Personal computer systems have dramatically improved the productivity of users through the continuing development of both hardware systems and software application products. Advantageously, the personal computer system should be simple to use, even for the most unskilled or wary user. The user interface to a personal computer system is most commonly via a display monitor and keyboard. The display monitor displays a text or graphic display suitable to the particular application program being run. The keyboard is used to enter commands or other information into the system.
When operating most programs, a "cursor" is displayed on the monitor to indicate the position on the display at which any data or instructions are to be entered. Initially, cursor control was provided with "arrow" keys on the keyboard, allowing the user to move the cursor in any direction one character or line at a time. More recently, pointing devices have been designed to simplify and provide more efficient cursor control. One such device is known as a light pen which is a light sensitive pickup device that is pointed at a display surface. A more popular recent development is the "mouse". A mouse is moved along a flat surface, with movement being sensed and translated into cursor movement on the display. Each of these devices is connected to the personal computer system with an electrical cord for transmitting electrical signals to the personal computer system. The requirement for the cord restricts what can be done with the mouse when not in use and limits the distance it can be from the system itself. Moreover, a mouse can only provide information indicating a relative change in cursor position from its last position. As a result, it may often be necessary to lift the mouse off of the flat surface and move it to provide additional cursor movement.
The present invention is directed to solving one or more of the problems discussed above.